diff --git a/installer/data/mysql/kohastructure.sql b/installer/data/mysql/kohastructure.sql
index cc9fb21e1d..c40ba6fe80 100644
--- a/installer/data/mysql/kohastructure.sql
+++ b/installer/data/mysql/kohastructure.sql
@@ -2824,7 +2824,8 @@ CREATE TABLE `aqorders_items` ( -- information on items entered in the acquisiti
   `itemnumber` int(11) NOT NULL, -- the item number for this item (items.itemnumber)
   `timestamp` timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP, -- the date and time this order item was last touched
   PRIMARY KEY  (`itemnumber`),
-  KEY `ordernumber` (`ordernumber`)
+  KEY `ordernumber` (`ordernumber`),
+  CONSTRAINT aqorders_items_ibfk_1 FOREIGN KEY (ordernumber) REFERENCES aqorders (ordernumber) ON DELETE CASCADE ON UPDATE CASCADE
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
 
diff --git a/installer/data/mysql/updatedatabase.pl b/installer/data/mysql/updatedatabase.pl
index 966ec9bbdc..3eb95c4ebd 100755
--- a/installer/data/mysql/updatedatabase.pl
+++ b/installer/data/mysql/updatedatabase.pl
@@ -6083,6 +6083,20 @@ if ( C4::Context->preference("Version") < TransformToNum($DBversion) ) {
     SetVersion($DBversion);
 }
 
+$DBversion = "3.11.00.XXX";
+if (C4::Context->preference("Version") < TransformToNum($DBversion)) {
+    $dbh->do(q{
+        DELETE from aqorders_items where ordernumber NOT IN (SELECT ordernumber FROM aqorders);
+    });
+    $dbh->do(q{
+        ALTER TABLE aqorders_items
+        ADD CONSTRAINT aqorders_items_ibfk_1 FOREIGN KEY (ordernumber) REFERENCES aqorders (ordernumber)
+        ON DELETE CASCADE ON UPDATE CASCADE;
+    });
+    print "Upgrade to $DBversion done (Bug 9030: Add constraint on aqorders_items.ordernumber)\n";
+    SetVersion ($DBversion);
+}
+
 =head1 FUNCTIONS
 
 =head2 TableExists($table)